Processability of hydrocarbon blown, polyisocyanate based foams through use of a compatibilizing agent

ABSTRACT

There is now provided a polyisocyanate-based foam made by an organic polyisocyanate with a polyol solution containing a C4-C7 aliphatic and/or cycloaliphatic hydrocarbon as a blowing agent. The hydrocarbon blowing agent is soluble in the polyol solution having polyols with polyester linkages by using a reacted or unreacted compatibilizing agent represented by the formula:   &lt;IMAGE&gt;   wherein R1 is preferentially OH, and R2 is a C6-C24 aliphatic, branched or unbranched, hydrocarbon group.

FIELD OF THE INVENTION

The present invention relates to rigid closed cell polyisocyanate basedfoams, and to the aromatic organic polyisocyanates and polyol solutionsused to make such foams. In particular, the invention relates to polyolsolutions containing a polyol having polyester linkages, a C₄ -C₇hydrocarbon blowing agent, and a reacted or unreacted compatibilizingagent.

BACKGROUND OF THE INVENTION

Recently, C₄ -C₇ hydrocarbon blowing agents have gained increasingimportance as zero ozone depletion potential alternative blowing agentsfor polyurethane foams. One problem associated with the use ofhydrocarbons is their low solubility in polyols and isocyanates. Blowingagent incompatibility with polyols can lead to processing difficultieson high pressure impingement mixing machines, most noticeably with thecalibration of the isocyanates/polyol ratio. The publication in the Oct.10-13th, 1993 issue of Polyurethanes World Congress entitled"Hydrocarbons Provide Zero ODP and Zero GWP Insulation for HouseholdRefrigeration" describes a foaming apparatus adapted for use with thehydrocarbon blowing agents. As can be seen from FIGS. 2 and 3 in thedescription of this publication, the hydrocarbon is separately meteredinto the mix head, or fed into a day tank which is kept under constantagitation. Most of the insulation foams use polyester-based polyols asthe base polyol, in which hydrocarbons have only a limited or nosolubility. Therefore, to avoid phase separation, the hydrocarbonblowing agent is either metered separately into the high pressure mixhead, or kept under constant agitation in a day tank immediately priorto being fed to the mixhead.

It would be desirable to avoid adding the hydrocarbon as a third streamto the mixhead. Since hydrocarbons tend to separate from the polyesterbased polyols within hours, sometimes minutes, after ceasing vigorousmixing, it would be desirable to formulate a polyol composition in whichthe hydrocarbon blowing agent is solubilized or held in solution withoutagitation. A hydrocarbon held as a solution in the polyol would have theadvantage of a more uniform distribution throughout the polyol.

SUMMARY OF THE INVENTION

There is now provided a polyol solution containing a polyol havingpolyester linkages, a blowing agent comprising an aliphatic orcycloaliphatic C₄ -C₇ hydrocarbon, and a reacted or unreactedcompatibilizing agent represented by the following formula: ##STR2##wherein R¹ is OH, NH₂, COOH, or oxyalkylated addition products thereof;and wherein R² is a C₆ -C₂₄ aliphatic, branched or unbranched,hydrocarbon group. The reacted or unreacted compatibilizing agentenables the hydrocarbon blowing agent to be solubilized in the polyolhaving polyester linkages. The resulting polyol solution is stable; andwhen mixed with an organic aromatic polyisocyanate, there is formed apolyisocyanate-based foam of good quality and a density range of 1.8 to2.2 pcf.

There is also provided a polyisocyanate-based foamable system of anorganic polyisocyanate component having dispersed therein a blowingagent and a polyol solution containing a polyol with polyester linkages,blowing agent, and the reacted or unreacted compatibilizer, where theblowing agent in both the organic polyisocyanate and in the polyolsolution is a C₄ -C₇ based aliphatic and/or cycloaliphatic hydrocarbon.

There is also provided a polyisocyanate-based foam and a method ofmaking such foam using a polyisocyanate-based foamable system asdescribed above.

DETAILED DESCRIPTION OF THE INVENTION

The C₄ -C₇ hydrocarbon blowing agents used in the invention, whencombined with a reacted or unreacted compatibilizer, form a solutionwith the polyols having polyester linkages. By a "solution" is meantthat the hydrocarbon blowing agent is uniformly dispersed throughout thepolyol having the polyester linkages in the absence of agitation andwithout phase separation for a period of at least 24 hours. The polyolsolutions prepared herein remain stable without phase separation foreven up to five days.

As the first ingredient in the polyol composition, there is provided ana) polyol having polyester linkages. Preferably, the total amount ofpolyols in the polyol solution having number average molecular weightsof 400 or more have an average functionality of 1.8 to 8, morepreferably 3 to 6, and an average hydroxyl number of 150 to 850, morepreferably 350 to 800. Polyols having hydroxyl numbers andfunctionalities outside this range may be used so long as the averagehydroxyl number for the total amount of polyols used fall within theaforementioned ranges.

Other types of polyols may be used in combination with the polyol havingpolyester linkages. Examples of polyols are thioether polyols, polyesteramides and polyacetals containing hydroxyl groups, aliphaticpolycarbonates containing hydroxyl groups, amine terminatedpolyoxyalkylene polyethers, polyoxyalkylene polyether polyols, and graftdispersion polyols. Mixtures of at least two of these polyols can beused so long as a polyol having polyester linkages is present in thepolyol solution in the aforesaid range.

The terms "polyol having polyester linkages" and "polyester polyol" asused in this specification and claims includes any minor amounts ofunreacted polyol remaining after the preparation of the polyester polyoland/or unesterified low molecular weight polyols (e.g., glycol) addedafter the preparation of the polyester polyol. The polyester polyol caninclude up to about 40 weight percent free glycol.

Polyols having polyester linkages broadly include any polyol having twoor more ester linkages in the compound, such as the conventionalpolyester polyols and the polyester-polyether polyols.

The polyester polyols advantageously have an average functionality ofabout 1.8 to 8, preferably about 1.8 to 5, and more preferably about 2to 3. The commercial polyester polyols used generally have averagehydroxyl numbers within a range of about 15 to 750, preferably about 30to 550, and more preferably about 150 to 500 (taking into account thefree glycols that may be present), and their free glycol contentgenerally is from about 0 to 40 weight percent, and usually from 2 to 15weight percent, of the total polyester polyol component. In calculatingthe average functionality and hydroxyl number of the total amount ofpolyols used in the polyol solution, the presence of the free glycols isnot taken into account because the glycols have number average molecularweights of less than 400.

Suitable polyester polyols can be produced, for example, from organicdicarboxylic acids with 2 to 12 carbons, preferably aliphaticdicarboxylic acids with 4 to 6 carbons and aromatic bound dicarboxylicacids, and multivalent alcohols, preferably diols, with 2 to 12 carbons,preferably 2 to 6 carbons. Examples of dicarboxylic acids includesuccinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid,sebacic acid, decanedicarboxylic acid, maleic acid, fumaric acid,phthalic acid, isophthalic acid, and terephthalic acid. The dicarboxylicacids can be used individually or in mixtures. Instead of the freedicarboxylic acids, the corresponding dicarboxylic acid derivatives mayalso be used such as dicarboxylic acid mono- or di- esters of alcoholswith 1 to 4 carbons, or dicarboxylic acid anhydrides. Dicarboxylic acidmixtures of succinic acid, glutaric acid and adipic acid in quantityratios of 20-35:35-50:20-32 parts by weight are preferred, as well asterephthalic acid and isophthalic acid and their 1-4 carbon esterderivatives. Examples of divalent and multivalent alcohols, especiallydiols, include ethanediol, diethylene glycol, 1,2- and 1,3-propanediol,dipropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,1,10-decanediol, glycerine and trimethylolpropanes, tripropylene glycol,tetraethylene glycol, tetrapropylene glycol, tetramethylene glycol,1,4-cyclohexane-dimethanol, ethanediol, diethylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, or mixtures of at leasttwo of these diols are preferred, especially mixtures of 1,4-butanediol,1,5-pentanediol, and 1,6-hexanediol. Furthermore, polyester polyols oflactones, e.g., ε-caprolactone or hydroxycarboxylic acids, e.g.,ω-hydroxycaproic acid, may also be used.

The polyester polyols can be produced by polycondensation of organicpolycarboxylic acids, e.g., aromatic or aliphatic polycarboxylic acidsand/or derivatives thereof and multivalent alcohols in the absence ofcatalysts or preferably in the presence of esterification catalysts,gererally in an atmosphere of inert gases, e.g., nitrogen, carbondioxide, helium, argon, etc., in the melt at temperatures of 150° to250° C., preferably 180° to 220° C., optionally under reduced pressure,up to the desired acid value which is preferably less than 10,especially less than 2. In a preferred embodiment, the esterificationmixture is subjected to polycondensation at the temperatures mentionedabove up to an acid value of 80 to 30, preferably 40 to 30, under normalpressure, and then under a pressure of less than 500 mbar, preferably 50to 150 mbar. The reaction can be carried out as a batch process orcontinuously. When present, excess glycol can be distilled from thereaction mixture during and/or after the reaction, such as in thepreparation of low free glycol-containing polyester polyols usable inthe present invention. Examples of suitable esterification catalystsinclude iron, cadmium, cobalt, lead, zinc, antimony, magnesium, titaniumand tin catalysts in the form of metals, metal oxides or metal salts.However, the polycondensation may also be preformed in liquid phase inthe presence of diluents and/or chlorobenzene for aziotropicdistillation of the water of condensation.

To produce the polyester polyols, the organic polycarboxylic acidsand/or derivatives thereof and multivalent alcohols are preferablypolycondensed in a mole ratio of 1:1-1.8, more preferably 1:1.05-1.2.

After transesterification or esterification, the reaction product can bereacted with an alkylene oxide to form a polyester-polyether polyolmixture. This reaction desirably is catalyzed. The temperature of thisprocess should be from about 80° to 170° C., and the pressure shouldgenerally range from about 1 to 40 atmospheres. While the aromaticpolyester polyols can be prepared from substantially pure reactantmaterials, more complex ingredients are advantageously used, such as theside stream, waste or scrap residues from the manufacture of phthalicacid, terephthalic acid, dimethyl terephthalate, polyethyleneterephthalate, and the like. Particularly suitable compositionscontaining phthalic acid residues for use in the invention are (a)ester-containing byproducts from the manufacture of dimethylterephthalate, (b) scrap polyalkylene terephthalates, (c) phthalicanhydride, (d) residues from the manufacture of phthalic acid orphthalic anhydride, (e) terephthalic acid, (f) residues from themanufacture of terephthalic acid, (g) isophthalic acid, (h) trimelliticanhydride, and (i) combinations thereof. These compositions may beconverted by reaction with the polyols of the invention to polyesterpolyols through conventional transesterification or esterificationprocedures.

Polyester polyols whose acid component advantageously comprises at leastabout 30 percent by weight of phthalic acid residues are useful. Byphthalic acid residue is meant the group: ##STR3##

A preferred polycarboxylic acid component for use in the preparation ofthe aromatic polyester polyols is phthalic anhydride. This component canbe replaced by phthalic acid or a phthalic anhydride bottomscomposition, a phthalic anhydride crude composition, or a phthalicanhydride light ends composition, as such compositions are defined inU.S. Pat. No. 4,529,744.

Other preferred materials containing phthalic acid residues arepolyalkylene terephthalates, especially polyethylene terephthalate(PET), residues or scraps.

Still other preferred residues are DMT process residues, which are wasteor scrap residues from the manufacture of dimethyl terephthalate (DMT).The term "DMT process residue" refers to the purged residue which isobtained during the manufacture of DMT in which p-xylene is convertedthrough oxidation and esterification with methanol to the desiredproduct in a reaction mixture along with a complex mixture ofbyproducts. The desired DMT and the volatile methyl p-toluate byproductare removed from the reaction mixture by distillation leaving a residue.The DMT and methyl p-toluate are separated, the DMT is recovered andmethyl p-toluate is recycled for oxidation. The residue which remainscan be directly purged from the process or a portion of the residue canbe recycled for oxidation and the remainder diverted from the processor, if desired, the residue can be processed further as, for example, bydistillation, heat treatment and/or methanolysis to recover usefulconstituents which might otherwise be lost, prior to purging the residuefrom the system. The residue which is finally purged from the process,either with or without additional processing, is herein called DMTprocess residue.

These DMT process residues may contain DMT, substituted benzenes,polycarbomethoxy diphenyls, benzyl esters of the toluate family,dicarbomethoxy fluorenone, carbomethoxy benzocoumarins and carbomethoxypolyphenols. Cape Industries, Inc. sells DMT process residues under thetrademark Terate® 101. DMT process residues having a differentcomposition but still containing the aromatic esters and acids are alsosold by DuPont and others. The DMT process residues to betransesterified in accordance with the present invention preferably havea functionality at least slightly greater than 2. Such suitable residuesinclude those disclosed in U.S. Pat. Nos. 3,647,759; 4,411,949;4,714,717; and 4,897,429; the disclosures of which with respect to theresidues are hereby incorporated by reference.

Examples of suitable polyester polyols are those derived from PET scrapand available under the designation Chardol 170, 336A, 560, 570, 571 and572 from Chardonol and Freol 30-2150 from Freeman Chemical. Examples ofsuitable DMT derived polyester polyols are Terate® 202, 203, 204, 254,2541, and 254A polyols, which are available from Cape Industries.Phthalic anhydride derived polyester polyols are commercially availableunder the designation Pluracol® polyol 9118 from BASF Corporation, andStepanol PS-2002, PS-2402, PS-2502A, PS-2502, PS-2522, PS-2852,PS-2852E, PS-2552, and PS-3152 from Stepan Company.

Polyoxyalkylene polyether polyols, which can be obtained by knownmethods, can be mixed with the polyol having polyester linkages. Forexample, polyether polyols can be produced by anionic polymerizationwith alkali hydroxides such as sodium hydroxide or potassium hydroxideor alkali alcoholates, such as sodium methylate, sodium ethylate, orpotassium ethylate or potassium isopropylate as catalysts and with theaddition of at least one initiator molecule containing 2 to 8,preferably 3 to 8, reactive hydrogens or by cationic polymerization withLewis acids such as antimony pentachloride, boron trifluoride etherate,etc., or bleaching earth as catalysts from one or more alkylene oxideswith 2 to 4 carbons in the alkylene radical. Any suitable alkylene oxidemay be used such as 1,3-propylene oxide, 1,2- and 2,3-butylene oxide,amylene oxides, styrene oxide, and preferably ethylene oxide and1,2-propylene oxide and mixtures of these oxides. The polyalkylenepolyether polyols may be prepared from other starting materials such astetrahydrofuran and alkylene oxide-tetrahydrofuran mixtures;epihalohydrins such as epichlorohydrin; as well as aralkylene oxidessuch as styrene oxide. The polyalkylene polyether polyols may haveeither primary or secondary hydroxyl groups.

Included among the polyether polyols are polyoxyethylene glycol,polyoxypropylene glycol,polyoxybutylene glycol, polytetramethyleneglycol, block copolymers, for example, combinations of polyoxypropyleneand polyoxyethylene glycols, poly-1,2-oxybutylene and polyoxyethyleneglycols, poly-1,4-tetramethylene and polyoxyethylene glycols, andcopolymer glycols prepared from blends or sequential addition of two ormore alkylene oxides. The polyalkylene polyether polyols may be preparedby any known process such as, for example, the process disclosed byWurtz in 1859 and Encyclopedia of Chemical Technology, Vol. 7, pp.257-262, published by Interscience Publishers, Inc. (1951) or in U.S.Pat. No. 1,922,459.

Polyethers which are preferred include the alkylene oxide additionproducts of polyhydric alcohols such as ethylene glycol, propyleneglycol, dipropylene glycol, trimethylene glycol, 1,2-butanediol,1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, hydroquinone,resorcinol glycerol, glycerine, 1,1,1-trimethylol-propane,1,1,1-trimethylolethane, pentaerythritol, 1,2,6-hexanetriol, α-methylglucoside, sucrose, and sorbitol. Also included within the term"polyhydric alcohol" are compounds derived from phenol such as2,2-bis(4-hydroxyphenyl)-propane, commonly known as Bisphenol A.

Suitable organic amine starting materials include aliphatic andcycloaliphatic amines and mixtures thereof, having at least one primaryamino group, preferably two or more primary amino groups, and mostpreferable are the diamines. Specific non-limiting examples of aliphaticamines include monoamines having 1 to 12, preferably 1 to 6 carbonatoms, such as methylamine, ethylamine, butylamine, hexylamine,octylamine, decylamine and dodecylamine; aliphatic diamines such as1,2-diaminoethane, propylene diamine, 1,4-diaminobutane,1,6-diaminohexane, 2,2-dimethyl-,3-propanediamine,2-methyl-1,5-pentadiamine, 2,5-dimethyl-2,5-hexanediamine, and4-aminomethyloctane-1,8-diamine, and amino acid-based polyamines such aslysine methyl ester, lysine aminoethyl ester and cystine dimethyl ester;cycloaliphatic monoamines of 5 to 12, preferably of 5 to 8, carbon-atomsin the cycloalkyl radical, such as cyclohexylamine and cyclo-octylamineand preferably cycloaliphatic diamines of 6 to 13 carbon atoms, such ascyclohexylenediamine, 4,4'-, 4,2'-, and 2,2'-diaminocyclohexylmethaneand mixtures thereof; aromatic monoamines of 6 to 18 carbon atoms, suchas aniline, benzylamine, toluidine and naphthylamine and preferablyaromatic diamines of 6 to 15 carbon atoms, such as phenylenediamine,naphthylenediamine, fluorenediamine, diphenyldiamine, anthracenediamine,and preferably 2,4- and 2,6-toluenediamine and 4,4'-, 2,4'-, and2,2'-diaminodiphenylmethane, and aromatic polyamines such as2,4,6-triaminotoluene, mixtures of polyphenyl-polymethylene-polyamines,and mixtures of diaminidiphenylmethanes andpolyphenyl-polymethylene-polyamines. Preferred are ethylenediamine,propylenediamine, decanediamine, 4,4'-diaminophenylmethane,4,4'-diaminocyclohexylmethane, and toluenediamine.

Suitable initiator molecules also include alkanolamines such asethanolamine, diethanolamine, N-methyl- and N-ethylethanolamine,N-methyl- and N-ethyldiethanolamine and triethanolamine plus ammonia.

Suitable polyhydric polythioethers which may be condensed with alkyleneoxides include the condensation product of thiodiglycol or the reactionproduct of a dicarboxylic acid such as is disclosed above for thepreparation of the polyester polyols with any other suitable thioetherglycol.

The polyester polyol may also be a polyester amide such as is obtainedby including some amine or amino alcohol in the reactants for thepreparation of the polyesters. Thus, polyester amides may be obtained bycondensing an amino alcohol such as ethanolamine with the polycarboxylicacids set forth above or they may be made using the same components thatmake up the polyester polyol with only a portion of the components beinga diamine such as ethylene diamine.

Polyhydroxyl-containing phosphorus compounds which may be used includethose compounds disclosed in U.S. Pat. No. 3,639,542. Preferredpolyhydroxyl-containing phosphorus compounds are prepared from alkyleneoxides and acids of phosphorus having a P₂ O₅ equivalency of from about72 percent to about 95 percent.

Suitable polyacetals which may be condensed with alkylene oxides includethe reaction product of formaldehyde or other suitable aldehyde with adihydric alcohol or an alkylene oxide such as those disclosed above.

Suitable aliphatic thiols which may be condensed with alkylene oxidesinclude alkanethiols containing at least two -SH groups such as1,2-ethanedithiol, 1,2-propanedithiol, 1,2-propanedithiol, and1,6-hexanedithiol; alkene thiols such as 2-butene-1,4-dithiol; andalkyne thiols such as 3-hexyne-1,6-dithiol.

Also suitable for mixture with the compound having polyester linkagesare polymer modified polyols, in particular, the so-called graftpolyols. Graft polyols are well known to the art and are prepared by thein situ polymerization of one or more vinyl monomers, preferablyacrylonitrile and styrene, in the presence of a polyether or polyesterpolyol, particularly polyols containing a minor amount of natural orinduced unsaturation. Methods of preparing such graft polyols may befound in columns 1-5 and in the Examples of U.S. Pat. No. 3,652,639; incolumns 1-6 and the Examples of U.S. Pat. No. 3,823,201; particularly incolumns 2-8 and the Examples of U.S. Pat. No. 4,690,956; and in U.S.Pat. No. 4,524,157; all of which patents are herein incorporated byreference.

Non-graft polymer modified polyols can also be mixed, for example, thoseprepared by the reaction of a polyisocyanate with an alkanolamine in thepresence of a polyol as taught by U.S. Pat. Nos. 4,293,470; 4,296,213;and 4,374,209; dispersions of polyisocyanurates containing pendant ureagroups as taught by U.S. Pat. No. 4,386,167; and polyisocyanuratedispersions also containing biuret linkages as taught by U.S. Pat. No.4,359,541. Other polymer modified polyols may be prepared by the in situsize reduction of polymers until the particle size is less than 20 μm,preferably less than 10 μm.

As a second ingredient in the polyol solution, there is provided a b)aliphatic or cycloaliphatic C₄ -C₇ hydrocarbon blowing agent. Theblowing agent should have a boiling point of 50° C. or less at oneatmosphere, preferably 38° C. or less.

The hydrocarbon is physically active and has a sufficiently low boilingpoint to be gaseous at the exothermic temperatures caused by thereaction between the isocyanate and polyols, so as to foam the resultingpolyurethane matrix. The hydrocarbon blowing agents consist exclusivelyof carbon and oxygen, therefore, they are non-halogenated by definition.Examples of the C₄ -C₇ hydrocarbon blowing agents include linear orbranched alkanes, e.g. butane, isobutane, 2,3 dimethylbutane, n- andisopentane and technical-grade pentane mixtures, n- and isohexanes, andn- and isoheptanes. Specific examples of alkenes are 1-pentene,2-methylbutene, 3-methylbutene, and 1-hexene, and of cycloalkanes arecyclobutane, preferably cyclopentane, cyclohexane or mixtures thereof.Preferentially, cyclopentane, n- and isopentane, (including theirtechnical grades) and mixtures thereof are employed.

Other blowing agents which can be used in combination with the one ormore C₄ -C₇ hydrocarbon blowing agents may be divided into thechemically active blowing agents which chemically react with theisocyanate or with other formulation ingredients to release a gas forfoaming, and the physically active blowing agents which are gaseous atthe exotherm foaming temperatures or less without the necessity forchemically reacting with the foam ingredients to provide a blowing gas.Included with the meaning of physically active blowing agents are thosegases which are thermally unstable and decompose at elevatedtemperatures.

Examples of chemically active blowing agents are preferentially thosewhich react with the isocyanate to liberate gas, such as CO₂. Suitablechemically active blowing agents include, but are not limited to, water,mono- and polycarboxylic acids having a molecular weight of from 46 to300, salts of these acids, and tertiary alcohols.

Water is preferentially used as a co-blowing agent with the hydrocarbonblowing agent. Water reacts with the organic isocyanate to liberate CO₂gas which is the actual blowing agent. However, since water consumesisocyanate groups, an equivalent molar excess of isocyanate must be usedto make up for the consumed isocyanates.

The organic carboxylic acids used are advantageously aliphatic mon- andpolycarboxylic acids, e.g. dicarboxylic acids. However, other organicmono- and polycarboxylic acids are also suitable. The organic carboxylicacids may, if desired, also contain substituents which are inert underthe reaction conditions of the polyisocyanate polyaddition or arereactive with isocyanate, and/or may contain olefinically unsaturatedgroups. Specific examples of chemically inert substituents are halogenatoms, such as fluorine and/or chlorine, and alkyl, e.g. methyl orethyl. The substituted organic carboxylic acids expediently contain atleast one further group which is reactive toward isocyanates, e.g. amercapto group, a primary and/or secondary amino group, or preferably aprimary and/or secondary hydroxyl group.

Suitable carboxylic acids are thus substituted or unsubstitutedmonocarboxylic acids, e.g. formic acid, acetic acid, propionic acid,2-chloropropionic acid, 3-chloropropionic acid, 2,2-dichlorpropionicacid, hexanoic acid, 2-ethyl-hexanoic acid, cyclohexanecarboxylic acid,dodecanoic acid, palmitic acid, stearic acid, oleic acid,3-mercapto-propionic acid, glycoli acid, 3-hydroxypropionic acid, lacticacid, ricinoleic acid, 2-aminopropionic acid, benzoic acid,4-methylbenzoic acid, salicylic acid and anthranilic acid, andunsubstituted or substituted polycarboxylic acids, preferablydicarboxylic acids, e.g. oxalic acid, malonic acid, succinic acid,fumaric acid, maleic acid, glutaric acid, adipic acid, sebacic acid,dodecanedioic acid, tartaric acid, phthalic acid, isophthalic acid andcitric acid. Preferable acids are formic acid, propionic acid, aceticacid, and 2-ethylhexanoic acid, particularly formic acid.

The amine salts are usually formed using tertiary amines, e.g.triethylamine, dimethylbenzylamine, diethylbenzylamine,triethylenediamine, or hydrazine. Tertiary amine salts of formic acidmay be employed as chemically active blowing agents which will reactwith the organic isocyanate. The salts may be added as such or formed insitu by reaction between any tertiary amine (catalyst or polyol) andformic acid contained in the polyol composition.

Combinations of any of the aforementioned chemically active blowingagents may be employed, such as formic acid, salts of formic acid,and/or water.

Physically active blowing agents are those which boil at the exothermfoaming temperature or less, preferably at 50° C. or less at 1atmosphere. The most preferred physically active blowing agents arethose which have an ozone depletion potential of 0.05 or less. Examplesof other physically active blowing agents are dialkyl ethers,cycloalkylene ethers and ketones; hydrochlorofluorocarbons (HCFCs);hydrofluorocarbons (HFCs); perfluorinated hydrocarbons (HFCs);fluorinated ethers (HFCs); and decomposition products.

Any hydrochlorofluorocarbon blowing agent may be used in the presentinvention. Preferred hydrochlorofluorocarbon blowing agents include1-chloro-1,2-difluoroethane; 1-chloro-2,2-difluoroethane (142a);1-chloro-1,1-difluoroethane (142b); 1,1-dichloro-1-fluoroethane (141b);1-chloro-1,1,2-trifluoroethane; 1-chloro-1,2,2-trifluoroethane;1,1-diochloro-1,2-difluoroethane; 1-chloro-1,1,2,2-tetrafluoroethane(124a); 1-chloro-1,2,2,2-tetrafluoroethane (124);1,1-dichloro-1,2,2-trifluoroethane; 1,1-dichloro-2,2,2-trifluoroethane(123); and 1,2-dichloro-1,1,2-trifluoroethane (123a);monochlorodifluoromethane (HCFC-22); 1-chloro-2,2,2-trifluoroethane(HCFC-133a); gem-chlorofluoroethylene (R-1131a);chloroheptafluoropropane (HCFC-217); chlorodifluoroethylene (HCFC-1122);and transchlorofluoroethylene (HCFC-1131). The most preferredhydrochlorofluorocarbon blowing agent is 1,1-dichloro-1-fluoroethane(HCFC-141b).

Suitable hydrofluorocarbons, perfluorinated hydrocarbons, andfluorinated ethers include difluoromethane (HFC-32);1,1,1,2-tetrafluoroethane (HFC-134a);1,1,2,2-tetrafluoroethane(HFC-134); 1,1-difluoroethane (HFC-152a);1,2-difluoroethane (HFC-142 ), trifluoromethane; heptafluoropropane;1,1,1-trifluoroethane; 1,1,2-trifluoroethane;1,1,1,2,2-pentafluoropropane; 1,1,1,3-tetrafluoropropane;1,1,2,3,3-pentafluoropropane; 1,1,1,3,3-pentafluoro-n-butane;hexafluorocyclopropane (C-216); octafluorocyclobutane (C-318);perfluorotetrahydrofuran; perfluoroalkyl tetrahydrofurans;perfluorofuran; perfluoro-propane, -butane, -cyclobutane, -pentane,-cyclopentane, and -hexane, -cyclohexane, -heptane, and -octane;perfluorodiethyl ether; perfluorodipropyl ether; and perfluoroethylpropyl ether.

Decomposition type physically active blowing agents which release a gasthrough thermal decomposition include pecan flour, amine/carbon dioxidecomplexes, and alkyl alkanoate compounds, especially methyl and ethylformates.

The total and relative amounts of blowing agents will depend upon thedesired foam density, the type of hydrocarbon, and the amount and typeof additional blowing agents employed. Polyurethane foam densitiestypical for rigid polyurethane insulation applications range from freerise densities of 1.3 to 2.5 pcf, preferably from 1.3 to 2.1 pcf, andoverall molded densities of 1.5 to 3.0 pcf. The amount by weight of allblowing agents is generally 10 php to 40 php, preferably 20 php to 35php (php means parts per hundred parts of all polyols). Based on theweight of all the foaming ingredients, the total amount of blowing agentis generally from 4 wt % to 15 wt %. The amount of hydrocarbon blowingagent, based on the weight of all the foaming ingredients, is also from4 wt. % to 15 wt %, preferably from 6 wt % to 10 wt %.

Water is typically found in minor quantities in the polyols as abyproduct and may be sufficient to provide the desired blowing from achemically active substance. Preferably, however, water is additionallyintroduced into the polyol solution in amounts from 0.05 to 5 pbw,preferably from 0.25 to 1.0 php.

As a third ingredient in the polyol solution, there is provided a c)reacted or unreacted compatibilizer represented by the followingformula: ##STR4## wherein R¹ is OH, NH₂, COOH, or oxyalkylated additionproducts thereof; and wherein R² is a C₆ -C₂₄ aliphatic, branched orunbranched, hydrocarbon group.

In one embodiment of the invention, the R¹ group is OH or anoxyalkylated addition product thereof; and R² is the saturated,unbranched (linear) hydrocarbon group. In another more preferredembodiment, R² is a C₈ -C₁₈ hydrocarbon group. For example, the reactedor unreacted compatibilizer may be a phenolic compound or oxyalkylatedproducts thereof, having a C₉ hydrocarbon radical attached to thearomatic ring, such as nonyl phenol or its oxyalkylated additionproduct. The hydrocarbon group R² may be attached to the aromatic ringin the ortho, meta, or para positions, or be a mixture of compoundshaving R₂ groups attached in different positions along the aromaticchain.

In another embodiment, the hydroxyl group of the formula reacted orunreacted compatibilizer may be oxyalkyated with ethylene oxide,propylene oxide, butylene oxide, or mixtures thereof, most preferablywith ethylene oxide, propylene oxide, or mixtures thereof. The reactedor unreacted compatibilizer may be oxyalkylated in a block fashion or ina heteric fashion. For example, the reacted or unreacted compatibilizermay contain an internal block of oxypropylene units condensed onto thehydroxyl group, with a terminal block of oxyethylene units.Alternatively, the reacted or unreacted compatibilizer may contain onlya block of oxyethylene units, or a mixture of oxyethylene andoxypropylene units, optionally as an internal block and capped withethylene oxide or propylene oxide. The molar quantities of theoxyalkylene groups can each vary from zero to three hundred (300), withthe number average molecular weight of the oxyalkylated compatibilizerranging from 250 to 12,000. Descriptions of the various types ofcompatibilizers and their methods of preparation may be found in U.S.Pat. Nos. 4,687,594; 4,644,048; 4,644,047; 4,608,432; and 4,722,803; thedisclosures of which each are incorporated herein by reference.

For purposes of this invention, the phrase "reacted or unreactedcompatibilizer" is taken to mean that the compatibilizer may be blendedwith the polyol having polyester linkages (unreacted), or thecompatibilizer may be used as a reactant in the manufacture of thepolyol having polyester linkages such as to covalently bond to thepolyol chain (reacted). For example, a reacted compatibilizer would beone that has been reacted together with a mixture of dicarboxylic acidcompound or derivative thereof such as phthalic acid, terephthalic acid,or DMT, and an aliphatic diol compound such as ethylene glycol. Themethods of preparation of reacted compatibilizers can also be found inU.S. Pat. Nos. 4,687,594; 4,644,048; 4,644,047; 4,608,432; and4,722,803; the entire disclosures of which each are incorporated hereinby reference.

The R¹ group should remain hydrophilic to compatibilize with the polarpolyester groups on the polyol, while the R² group is hydrophobic tocompatibilize with the hydrophobic C₄ -C₇ hydrocarbon blowing agent.While the R² group may be branched, it is preferable that the branching,if present, be located within 1-3 carbon atoms closest to the aromaticring; and most preferably, the branched groups are C₁ -C₃ alkyl groups.Generally, however, the hydrocarbon group is linear to provide greaterhydrophobicity.

The amount of reacted or unreacted compatibilizer is effective to bringthe amount of hydrocarbon into solution with the polyol having polyesterlinkages. This amount will vary depending upon the type of reacted orunreacted compatibilizer used, the type of hydrocarbon used, the amountof hydrocarbon, and the kind of polyol having polyester linkages used.Generally, however, the amount of reacted or unreacted compatibilizerwill range from 1 to 30 php.

Additional optional ingredients in the polyol solution may includeisocyanate and/or isocyanurate promoting catalysts, surfactants, flameretardants, and fillers.

Catalysts may be employed which greatly accelerate the reaction of thecompounds containing hydroxyl groups and with the modified or unmodifiedpolyisocyanates. Examples of suitable compounds are cure catalysts whichalso function to shorten tack time, promote green strength, and preventfoam shrinkage. Suitable cure catalysts are organometallic catalysts,preferably organotin catalysts, although it is possible to employ metalssuch as lead, titanium, copper, mercury, cobalt, nickel, iron, vanadium,antimony, and manganese. Suitable organometallic catalysts, exemplifiedhere by tin as the metal, are represented by the formula: R_(n) Sn[X--R¹--Y]₂, wherein R is a C₁ -C₈ alkyl or aryl group, R¹ is a C₀ -C₁₈methylene group optionally substituted or branched with a C₁ -C₄ alkylgroup, Y is hydrogen or an hydroxyl group, preferably hydrogen, X ismethylene, an --S--, an --SR² COO--, --SOOC--, an --O₃ S--, or an--OOC-- group wherein R² is a C₁ -C₄ alkyl, n is 0 or 2, provided thatR¹ is C₀ only when X is a methylene group. Specific examples are tin(II) acetate, tin (II) octanoate, tin (II) ethylhexanoate and tin (II)laurate; and dialkyl (1-8C) tin (IV) salts of organic carboxylic acidshaving 1-32 carbon atoms, preferably 1-20 carbon atoms, e.g., diethyltindiacetate, dibutyltin diacetate, dibutyltin diacetate, dibutyltindilaurate, dibutyltin maleate, dihexyltin diacetate, and dioctyltindiacetate. Other suitable organotin catalysts are organotin alkoxidesand mono or polyalkyl (1-8 C) tin (IV) salts of inorganic compounds suchas butyltin trichloride, dimethyl- and diethyl- and dibutyl- anddioctyl- and diphenyl- tin oxide, dibutyltin dibutoxide,di(2-ethylhexyl) tin oxide, dibutyltin dichloride, and dioctyltindioxide. Preferred, however, are tin catalysts with tin-sulfur bondswhich are resistant to hydrolysis, such as dialkyl (1-20 C) tindimercaptides, including dimethyl-, dibutyl-, and dioctyl- tindimercaptides.

Tertiary amines also promote urethane linkage formation, and includetriethylamine, 3-methoxypropyldimethylamine, triethylenediamine,tributylamine, dimethylbenzylamine, N-methyl-, N-ethyl- andN-cyclohexylmorpholine, N,N,N',N'-tetramethylethylenediamine,N,N,N',N'-tetramethylbutanediamine or -hexanediamine, N,N,N'-trimethylisopropyl propylenediamine, pentamethyldiethylenetriamine,tetramethyldiaminoethyl ether, bis(dimethylaminopropyl)urea,dimethylpiperazine, 1-methyl-4-dimethylaminoethylpiperazine,1,2-dimethylimidazole, 1-azabicylo[3.3.0]octane and preferably1,4-diazabicylo[2.2.2]octane, and alkanolamine compounds, such astriethanolamine, triisopropanolamine, N-methyl- andN-ethyldiethanolamine and dimethylethanolamine.

To prepare the polyisocyanurate (PIR) and the PUR-PIR foams of theinvention, a polyisocyanurate catalyst is employed. Suitablepolyisocyanurate catalysts are alkali salts, for example, sodium salts,preferably potassium salts and ammonium salts, of organic carboxylicacids, expediently having from 1 to 8 carbon atoms, preferably 1 or 2carbon atoms, for example, the salts of formic acid, acetic acid,propionic acid, or octanoic acid, and tris(dialkylaminoethyl)-,tris(dimethylaminopropyl)-, tris(dimethylaminobutyl)- and thecorresponding tris(diethylaminoalkyl)-s-hexahydrotriazines. However,(trimethyl-2-hydroxypropyl)ammonium formate,(trimethyl-2-hydroxypropyl)ammonium octanoate, potassium acetate,potassium formate and tris(diemthylaminopropyl)-s-hexahydrotriazine arepolyisocyanurate catalysts which are generally used. The suitablepolyisocyanurate catalyst is usually used in an amount of from 1 to 10php, preferably from 1.5 to 8 php. In addition to using apolyisocyanurate catalyst, the organic isocyanates are generally reactedwith the polyol solution at an isocyanate index of 200 or more,preferably between 250 to 350, in the manufacture of PIR foams.

Examples of suitable flame retardants are tetrakis(2-chloroethyl)ethylene phosphonate, tris(1,3-dichloropropyl) phosphate,tris(beta-chloroethyl) phosphate, tricresyl phosphate,tris(2,3-dibromopropyl)phosphate,tris(beta-chloropropyl)phosphate,tricresyl phosphate, andtris(2,3-dibromopropyl) phosphate.

In addition to the above-mentioned halogen-substituted phosphates, it isalso possible to use inorganic or organic flameproofing agents, such asred phosphorus, aluminum oxide hydrate, antimony trioxide, arsenicoxide, ammonium polyphosphate (Exolit®) and calcium sulfate, expandablegraphite or cyanuric acid derivatives, e.g., melamine, or mixtures oftwo or more flameproofing agents, e.g., ammonium polyphosphates andmelamine, and, if desired, corn starch, or ammonium polyphosphate,melamine, and expandable graphite and/or, if desired, aromaticpolyesters, in order to flameproof the polyisocyanate polyadditionproducts. In general, from 2 to 50 php, preferably from 5 to 25 php, ofsaid flameproofing agents may be used.

Optional fillers are conventional organic and inorganic fillers andreinforcing agents. Specific examples are inorganic fillers, such assilicate minerals, for example, phyllosilicates such as antigorite,serpentine, hornblendes, amphiboles, chrysotile, and talc; metal oxides,such as kaolin, aluminum oxides, titanium oxides and iron oxides; metalsalts, such as chalk, baryte and inorganic pigments, such as cadmiumsulfide, zinc sulfide and glass, inter alia; kaolin (china clay),aluminum silicate and coprecipitates of barium sulfate and aluminumsilicate, and natural and synthetic fibrous minerals, such aswollastonite, metal, and glass fibers of various lengths. Examples ofsuitable organic fillers are carbon black, melamine, colophony,cyclopentadienyl resins, cellulose fibers, polyamide fibers,polyacrylonitrile fibers, polyurethane fibers, and polyester fibersbased on aromatic and/or aliphatic dicarboxylic acid esters, and inparticular, carbon fibers.

The inorganic and organic fillers may be used individually or asmixtures and may be introduced into the polyol composition or isocyanateside in amounts of from 0.5 to 40 percent by weight, based on the weightof components (the polyols and the isocyanate); but the content of mats,nonwovens and wovens made from natural and synthetic fibers may reachvalues of up to 80 percent by weight.

There is also provided as part of the invention a polyisocyanate-basedfoamable composition made up of an organic isocyanate component and apolyol solution component, where the blowing agent is dispersed in thepolyol solution or dispersed in both the isocyanate component and thepolyol solution. In one embodiment of the invention, anywhere from 10-20php of the C₄ -C₇ hydrocarbon blowing agent is dispersed uniformly inthe aromatic organic polyisocyanate; and 10-20 php of the hydrocarbonblowing agent is also dispersed uniformly in the polyol solution. Theexact amount of hydrocarbon blowing agent used in the aromatic organicpolyisocyanate and the polyol solution will depend upon the desireddensity and solubility limits of each component.

The organic polyisocyanates include all essentially known aliphatic,cycloaliphatic, araliphatic and preferably aromatic multivalentisocyanates. Specific examples include: alkylene diisocyanates with 4 to12 carbons in the alkylene radical such as 1,12-dodecane diisocyanate,2-ethyl-1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentamethylenediisocyanate, 1,4-tetramethylene diisocyanate and preferably1,6-hexamethylene diisocyanate; cycloaliphatic diisocyanates such as1,3- and 1,4-cyclohexane diisocyanate as well as any mixtures of theseisomers, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane(isophorone diisocyanate), 2,4- and 2,6-hexahydrotoluene diisocyanate aswell as the corresponding isomeric mixtures, 4,4'-2,2'-, and2,4'-dicyclohexylmethane diisocyanate as well as the correspondingisomeric mixtures and-preferably aromatic diisocyanates andpolyisocyanates such as 2,4- and 2,6-toluene diisocyanate and thecorresponding isomeric mixtures 4,4'-, 2,4'-, and 2,2'-diphenylmethanediisocyanate and the corresponding isomeric mixtures, mixtures of 4,4'-and 2,4'-diphenylmethane diisocyanates and polyphenylenepolymethylenepolyisocyanates (polymeric MDI), as well as mixtures of polymeric MDIand toluene diisocyanates. The organic di- and polyisocyanates can beused individually or in the form of mixtures.

Frequently, so-called modified multivalent isocyanates, i.e., productsobtained by the partial chemical reaction of organic diisocyanatesand/or polyisocyanates are used. Examples include diisocyanates and/orpolyisocyanates containing ester groups, urea groups, biuret groups,allophanate groups, carbodiimide groups, isocyanurate groups, and/orurethane groups. Specific examples include organic, preferably aromatic,polyisocyanates containing urethane groups and having an NCO content of33.6 to 15 weight percent, preferably 31 to 21 weight percent, based onthe total weight, e.g., with low molecular weight diols, triols,dialkylene glycols, trialkylene glycols, or polyoxyalkylene glycols witha molecular weight of up to 1500; modified 4,4'-diphenylmethanediisocyanate or 2,4- and 2,6-toluene diisocyanate, where examples of di-and polyoxyalkylene glycols that may be used individually or as mixturesinclude diethylene glycol, dipropylene glycol, polyoxyethylene glycol,polyoxypropylene glycol, polyoxyethylene glycol, polyoxypropyleneglycol, and polyoxypropylene polyoxyethylene glycols or-triols.Prepolymers containing NCO groups with an NCO content of 25 to 9 weightpercent, preferably 21 to 14 weight percent, based on the total weightand produced from the polyester polyols and/or preferably polyetherpolyols described below; 4,4'-diphenylmethane diisocyanate, mixtures of2,4'- and 4,4'-diphenylmethane diisocyanate, 2,4,- and/or 2,6-toluenediisocyanates or polymeric MDI are also suitable. Furthermore, liquidpolyisocyanates containing carbodiimide groups having an NCO content of33.6 to 15 weight percent, preferably 31 to 21 weight percent, based onthe total weight, have also proven suitable, e.g., based on 4,4'- and2,4'- and/or 2,2'-diphenylmethane diisocyanate and/or 2,4'- and/or2,6-toluene diisocyanate. The modified polyisocyanates may optionally bemixed together or mixed with unmodified organic polyisocyanates such as2,4'- and 4,4'-diphenylmethane diisocyanate, polymeric MDI, 2,4'-and/or2,6-toluene diisocyanate.

Preferably, the isocyanate used to make the closed cell rigid foams ofthe invention contain polymeric MDI, with the average functionality ofthe isocyanate component used to react with the polyol composition being2.2 or more, more preferably 2.5 or more, most preferably 2.7 or more.

The foams of the invention are closed cell, meaning that greater than80% of the cells are closed as measured for uncorrected porosity.Preferably, greater than 85%, more preferably 90% or more of the cellsare closed as measured for uncorrected porosity. The foams of theinvention are also rigid, meaning that they have a compressive strengthto tensile strength ratio of at least 1.0 and an elongation at yield ofless than 10%.

The foams of this invention are polyisocyanate based, meaning that thefoams may be considered polyurethane, polyisocyanurate, or any mixtureof the two linkages. In a method of the invention, an organic aromaticpolyisocyanate having dispersed therein the C₄ -C₇ hydrocarbon blowingagent, and a polyol solution having dispersed therein the same blowingagent, are fed through two separate lines to a high pressure impingementmixhead. The components are intimately mixed under high pressure forless than two (2) seconds and dispensed through the mixhead onto asubstrate, such as a conveyor belt, a facer, or a mold surface. Thefoamable mixed composition is allowed to foam and cure. Applications forthe foams made by the present invention are laminate board for buildingand housing insulation, refrigeration appliance cabinets, entry way doorinsulation, and any other application requiring rigid polyisocyanatefoams using polyester-based polyols.

Polyol A is Terate 2541, a polyester polyol derived from DMT andcommercially available from Cape Industries.

Polyol B is Weston PTP, a phosphite initiated polyol commerciallyavailable from General Electric Company.

Polyol C is Stepanpol 2502, a polyester polyol derived from phthalicanhydride containing a reacted compatibilizing agent based on a phenoliccompound, commercially available from Stepan.

B-8462 is a silicone surfactant commercially available from Goldschmidt.

Polycat 5 is pentamethyl-diethylene triamine, a catalyst for rigid foamapplications commercially available from Air Products.

Isocyanate A is a polymeric MDI having a free NCO content of 31.4, aviscosity of about 700 cps at 23° C., and having a functionality greaterthan 2.7, commercially available from BASF Corporation.

EXAMPLE 1

In this example, cyclopentane as a blowing agent was dispersed in boththe isocyanate component and the polyol solution component in theamounts stated in Table I below. The polyol solution ingredients weremixed in a stainless steel, open top container for about thirty (30)minutes. The stainless steel container was positioned on a scale tomeasure the weight of the ingredients during the blending operation, andany cyclopentane gas escaping during the mixing operation wascontinually replenished to keep the parts by weight of the gas constant.The contents of the premix tank were transferred to the resin day tankof a high pressure impingement metering unit and continuously agitatedand ciruculated through an in-line static mixer to prevent cyclopentaneseparation. When a shot of material was required, the polyol compositionin the day tank was pumped to the mixhead, where it was impingementmixed with Iso A having dispersed therein cyclopentane. The calibrationof the machine is stated in Table I below. The impingement mixed polyolsolution and isocyanate were shot into 165 oz. cups for measurement offoam reactivity and density, into 4"×10"×10" (L×W× H) molds for freerise and 10% packed samples, and into molds measuring 48"×12"×1.5" atthe times and weights stated in Table I. The foams had suitabledensities and uniform cell structures, indicating that the hydrocarbonblowing agent was uniformly dispersed into the polyol and isocyanate.

                  TABLE I                                                         ______________________________________                                        Samples            1          2                                               ______________________________________                                        Polyol A           20         20                                              Polyol B           20         20                                              Polyol C           60         60                                              B-8404             2.0        8.0                                             HexChem 977        3.5        3.5                                             Polycat 5          0.5        0.5                                             Cyclopentane       15         15                                              Water              0.5        0.5                                             Total              121.5      127.5                                           Iso A              202.72     202.72                                          Cyclopentane       15         15                                              Index              300        300                                             #10 Lilly Cup, pcf,                                                                              1.63       1.64                                            Reactivity (seconds)                                                          Shot Time          2.5        2.5                                             Cream              5.2        --                                              Gel                20         20                                              Rise               76         78                                              Tack-Free          41         36                                              Free-Rise Box                                                                 Weight             190        201.3                                           Pcf                1.81       1.92                                            Shrinkage          Yes        Yes                                             Friability         None       None                                            10 Percent Packed Box                                                         Weight, grams      209.0      224.3                                           Pcf                1.99       2.13                                            Door Mold                                                                     Shot               5.56       5.90                                            Weight             435        468                                             pcf free rise      1.97       2.06                                            Shot               6.28       6.48                                            Weight             487        516                                             pcf, packed        2.15       2.27                                            Calibration                                                                   Resin              87.3       91.8                                            Iso                155.9      155.6                                           RPM Resin          586        618                                             RPM Iso            950        850                                             Pressure Resin     1900       2000                                            Pressure Iso       2000       2000                                            ______________________________________                                    

The results above indicate that polyisocyanurate foams can be made atsuitable densities using a high pressure machine by dissolvingcyclopentane and the isocyanate and the polyester polyol using nonylphenol as a reacted or unreacted compatibilizing agent.

EXAMPLE 2

In this example, studies were conducted to determine the solubilitylimits of cyclopentane in an isocyanate and polyols. In each sample,cyclopentane was added to either the isocyanate or the polyol, mixeduntil uniformly dispersed, and then left standing for at least four dayswithout agitation or movement. Subsequently, each sample was examinedfor phase separation between the cyclopentane and the polyol orisocyanate.

In samples 3-7, cyclopentane at the weight percentages indicated belowwas mixed with Isocyanate A.

    ______________________________________                                        Samples       Cyclopentane                                                                             Separation                                           ______________________________________                                        3              5 percent No                                                   4             10 percent No                                                   5             15 percent No                                                   6             20 percent No                                                   7             25 percent Yes                                                  ______________________________________                                    

The results above indicate that cyclopentane is miscible with Iso A atcyclopentane levels of up to about 20 percent. At 25 percent, phaseseparation was evident.

Cyclopentane was added to a blend of polyols comprising 80 parts byweight of Polyol A and 20 parts by weight of Polyol B.

    ______________________________________                                        Samples       Cyclopentane                                                                             Separation                                           ______________________________________                                        8             16 percent Yes                                                  9             21 percent Yes                                                  10            27 percent Yes                                                  ______________________________________                                    

The results of Samples 8-10 indicate that cyclopentane phase separatedwithin four days without the use of a reacted or unreactedcompatibilizing agent.

In samples 11-14 described below, cyclopentane was maintained atconstant levels in different polyol blends. A description of each polyolblend and the level of cyclopentane loadings is listed below along withthe results on phase separation. All numbers indicated below are inparts by weight. The polyol blend employed was a mixture of Polyol A,Polyol B, and Polyol C, with different amounts reported belowcorresponding to each polyol respectively. Polyol C is a polyol thatcontains nonyl phenol as a reacted or unreacted compatibilizing agent.

                  TABLE II                                                        ______________________________________                                                 BLEND        CYCLO-                                                  SAMPLES  PROPORTIONS  PENTANE    SEPARATION                                   ______________________________________                                        11       80/20/0      15 pbw     Yes                                          12       60/20/20     15 pbw     Yes                                          13       40/20/40     15 pbw     Yes                                          14       20/20/60     15 pbw     No                                           ______________________________________                                    

The results of these experiments indicate that the nonyl phenol reactedor unreacted compatibilizing agent in Polyol C was at a high enoughlevel in Sample 14 to effectively solubilize cyclopentane in thepolyester polyols. Without the presence of the reacted or unreactedcompatibilizing agent nonyl phenol, as in Sample 11, cyclopentane wouldnot form a solution with the polyester polyols.

What we claim is:
 1. A polyol solution comprising:a) a polyol havingpolyester linkages; b) a blowing agent comprising an aliphatic orcycloaliphatic C₄ -C₇ hydrocarbon; c) a reacted or unreactedcompatibilizer represented by the following formula: ##STR5## wherein R¹is OH, NH₂, COOH, or oxyalkylated addition products thereof; and R² is aC₆ -C₂₄ aliphatic, branched or unbranched, hydrocarbon group.
 2. Thepolyol solution of claim 1, wherein R¹ comprises OH or oxyalkylatedaddition products thereof, and R² is a saturated, unbranched,hydrocarbon group.
 3. The polyol solution of claim 2, wherein thereacted or unreacted compatibilizer comprises nonyl phenol or theoxyalkylated addition products thereof.
 4. The polyol solution of claim2, wherein the blowing agent comprises n-pentane, isopentane,cyclopentane, or mixtures thereof.
 5. The polyol solution of claim 4,wherein the blowing agent further comprises water.
 6. The polyolsolution of claim 4, wherein the polyol comprises an aromatic polyesterpolyol.
 7. The polyol solution of claim 1, comprising 10-20 php of thehydrocarbon blowing agent.
 8. The polyol solution of claim 1, wherein R¹is OH or oxyalkylated addition products thereof; the polyol comprises anaromatic polyester polyol; and the blowing agent comprises n-pentane,isopentane, cyclopentane, or mixtures thereof.
 9. The polyol solution ofclaim 8, comprising a polyol derived from dimethyl terephthalate,phthalic acid, terephthalic acid, polyethylene terephthalate, theanhydrides thereof, or mixtures thereof, and the compatibilizer isreacted.
 10. The polyol solution of claim 1, comprising a polyol derivedfrom dimethyl terephthalate or phthalic anhydride; a blowing agentcomprising n-pentane, isopentane, cyclopentane, or mixtures thereof; anda reacted compatibilizer comprising nonyl phenol or oxyalkylatedaddition products thereof.
 11. The polyol solution of claim 10, whereinthe blowing agent comprises cyclopentane.
 12. The polyol solution ofclaim 11, wherein the blowing agent comprises cyclopentane in an amountof 10-20 php, and water.